Method of making acoustic diaphragms.



W. W. YOUNG.

METHOD or MAKING AcoUsTIc DIAPHRAGMS.

APPLICATION FILED SEPT. 23, 1910.

Patented May 19, 1914.

HITNESSES:

UNITED YOU 1? AGAWAM, MASSACHUSETTS, ASSIGNOR, BY MESNE AS$IGN- WILLIAM w.

raTENT OFFICE.

Specification of Letterslatcnt.

Patented May 19, 1914,

original a plication filed September 7, 1909, Serial No. 516,555, Divided and this applicationfiled September 23, rate.

Serial. 35"0. $333,353,

To all 1071 am it may concern:

Be it known that I, WILLIAM W. YOUNG, a citizen of the United States of America, residing at 'Agawam, in the county of Hampden and State of Massachusetts, have invented a new and useful Method of Making Acoustic Diaphragms, of which the following is a specification, the same being a divisional part of my application Serial No. 516,555, filed in the United States Patent Oflice September 7 1909.

My invention relates to improvements in methods of making acoustic diaphragms for talking-machines, telephones, and the like, and consists broadly and generally in roughcning or indenting one or bothv surfaces or faces of a diaphragmal member and applying thereto a compound, emulsion, solution, or mixture which is capable of hardening and forming a coating and of permanently uniting with said member, as hereinafter set forth.

The object of my invention is to produce an acoustic diaphragm, of the class mentioned above, which possesses superlatively in addition to the absolutely essential the otherwise desirable and long sought characteristics and qualities of a device of this kind, among which characteristics and qualities mention may be made here of durability and stability, resiliency and resonance, capability of giving out clear, loud and distinct tones of great volume and depth, and of evenly distributing the sound waves, and immunity from blasts and scratching sounds and other alien and discordant noises.

Other objects will appear in the course of the following description.

A diaphragm constructed in accordance with the method broadly and generally outlined above may be improved for some an probably many purposes by perforating it and transforming the perforations or perforated parts into lesser diaphragms, or even. by perforating and leaving the perforations open, as will be subsequently explained.

In the accompanying drawings, which form part of this application and in which like characters of reference indicate like parts throughout the several viewsFigure Z 1 is a face View of an imperforate diaphragm,.and Fig. 2, a similar view of a perforated diaphragm, both made in accordance with my method; Figs. 3, 4 and 5, each a face view of a diaphragm including some form of the lesser-diaphragmal feature and made in, accordance with said method, and. Fig. 6, a face View of a diaphragm pro duced in the same manner as the others except that it is checked instead of pitted.

I will now explain in detail how the diaphragm is produced, but wish first to state that said diaphragm may be made individually, that is, by itself, or a strip or sheet may be prepared and the diaphragm out from that, whichever way is most practical with any given. material or materials. For the sake of brevity I will apply the following (lGSGIIPlIIOII tO a. single dia hragm, with the understanding that such i-aphragm might constitute a part of a strip or sheet from which it is to be out at some particular stage or at the end of the manufacturing process.

In the simplest or primary form 0 my invention, that shown in either the first or last view, I take a disk 1 of some suitable material and by means of dies or other suitable appliances or instruments pit in the first nstance and check n the second instance 1 one or both surfaces, preferably both, of 5 said disk, and the-n treat the pitted or checked disk with a compound, emulsion, so-

lution or mixture which possesses the neces sary qualifications, or if the disk be of fiber then the pitting or checking is not i done until after first applying such mixture. The. pits, represented at, 2, and the checks, rep resented at 3, may be re lar or not, as desired, but are usually quite small and close together, although for some purposes and in some cases they will be coarse. Consider able latitude should be allowed in the matter of breaking up, roughening or indenting the surface or surfaces of the disk, since the d i only essential thing is to obtain the unevenness, although for talking-machines the pit- ?ted diaphragbm has been found to give as good if not etter results than one having merely roughened surfaces. The checking approaches very closely in effect and result the pitting, but if in place of the former either set of cross cuts was omitted, as might ;be done, the appearance at least would be changed and it is doubtful if the results would equal those obtained in the other cases. As already noted, however, I do not desire or intend to be limited to any particular means for or method of, roughening, n-

denting, or otherwise rendering irregular the disk surfaces, nor to any particular design for such surfaces.

The aforesaid mixture is applied to the disk 1, after indenting if a metallic disk and before if a fibrous disk be used, in any convenient manner, generally by dipping the latter in the former, although such mixture might be put on with a brush or its equiyalent. After receiving or being coated with the proper amount of the mixture, the disk thusprepared, if of fiber, is exposed to air or subjected to heat to partlally dry the coating, then it is pressed between sultable dies to indent it, next the treated and indented disk is again treated with the mixture, and finally it is baked. After coating the indented metallic disk one or more times, and partially drying if more than one coat be applied, the same is baked. The resulting diaphragm in either case is an excellent acoustic medium, such as I-have defined in the early part of this specification. I

A variety of different kinds of metallic and non-metallic materials may be employed for the disk 1, but any material to be thus employed should be thin and must be of a nature well adapted to take the mixture when properly applied thereto and enable such mixture to unite therewith, and possess the necessary qualities of then producing the desired efiect. Thin sheet-aluminum and pure linen-fiber paper or card-board are among the best materials and give some of the best results.

The imperforate diaphragms shown in Figs. 1 and 6 are the resulting products of the method hereinbefore outlined. In Fig. 2 appears a diaphragm having a number of perforations 4 therein, otherwise it is similar to the two just mentioned and is pro-,

duced by the same method. The perforations are generally out before the mixture is applied to the disk. The surfaces of the Fig. 2 diaphragm may be checked like those of the Fig. 6 diaphragm, instead of bein pitted and having the resulting pebbly e fect indicated in all of the views except the last, and this is true of the Figs. 3, 4 and 5 diaphragms. So, also, is it true that any kind of surface roughening or indenting which is applicable to one form of diaphragm is applicable to all.

For many 1f not most uses to which my diaphragm is to be put, I find it very advantageous to perforate the disk 1 and to cover such perforations With very thin material, such as tissue paper for example, which forms lesser or minor diaphragms 5 on or in the diaphragm proper or major diaphragm. These lesser diaphragmsmay be made by using individual disks 6 with which tocover the perforations 4 separately, as in Fig. 3; or a ring 7 with which to cover the perforations collectively, as in Fig. 4:;

.plain or unindented condition, but after a first application of said mixture, nevertheless; then more of the mixture is applied, and the disk with its accretions is baked, excepting in the case of the fibrous disk which must be partially dried and subjected to the dies which indent it before the second application of the mixture and the baking. The method in either of the above cases is the same as that previously described, with the lesser-diaphragmal feature added.

The integument is so applied to the disk that it forms a close union therewith at substantially all points in the area of said integument.

The perforations 4 may be of various shapes and sizes, arranged in any desired form regularly or irregularly, and more or less numerous in any given case.

The material or combination of materials used for coating the disks, and the integuments when present, inclu'ding both sides of the lesser diaphragms 5, must be of such a nature that the same will adhere firmly to the parts and saturate or impregnate the fibrous disks, and also cause such integuments to adhere firmly to the disks; furthermore, the nature of the coating must be such that it will so unite with the other elements and harden during the-process of manufacturing the diaphragms as to produce devices having the required stability, permanence and excellence.

I prefer to employ for such coating silicate of soda or silicate of potash, oxid of zinc, and an earth cement, the proportions of which may vary to some considerable extent without seriously afi'ecting the efiiciency of the mixture made therefrom. As a working basis for compounding the mixture, however, one part each of the oxid of zinc and the cement to twenty parts of the silicate of soda or silicate of pot-ash may be taken. The mixture in baking becomes hard and in this condition is fixed on the disks, and in them when fibrous, to which it is applied and firmly, completely and permanently unites the several elements or materials into an integrate structure.

In addition to the variations already noted others may be made without departin from the nature of my invention.

at I claim as my invention, and desire to secure by Letters Patent, is-

1. The method of making acoustic diaphragms, of the class described, consisting in perforating suitable thin material, in applying a suitable coating to such material and causing the same to harden thereon, and in applying a suitable integulnent to the perforated parts of said material, while the coating on said material is in a moist condition and without covering the entire area of the material With the intcgument, and in surface breaking said material at some stage in the rocess of manufacture.

2. T e method of making acoustic diaphragms, of the class described, consisting in perforating a disk of sultable material, in applying a suitable coating to such disk, 1n applying to the perforated parts of the coated disk, without covering the entire disk, a suitable integument, the latter being applied while such coating is in a moist condition, 1n again applying the coating and causing the same to harden, and in surface breaking said disk at some stage in the proc- WVILLIAM W. YOUNG.

Witnesses F. A. CUTTER,

A. C. FAIRBANKS. 

